Environmental control systems typically have a plurality of components connected by ducts. Occasionally, some of those components, such as heat exchangers, must be pressure or leakage tested to ensure their operational integrity. In order to pressure or leakage test a component, the input and output ducts of the component must be sealed off. Some input and output ducts, however, lack a positive means of attachment, such as a flange or bead, to attach a seal to those ducts. Because such component ducts lack a positive means of attachment, it is difficult to seal the component duct before pressure or leakage testing.